Translucent petroleum plastic



' May 21, 1940;

A. P. ANDERSON TRANSLUCENT PETROLEUM PLASTIC Filed Jan. 21; 1938.

5 Sheets-Sheet 2 um 6 Plasfic B E Cal/forn'a 3' P/asficA H r V 4 2 flours heafed vi 325 [4 5 TM 0613.? mclhad) Fig. Z.

Change in penefrafion upon heaf/ng of pefra/eum plasfics A 4 B I30 "J k/lo v 5 P/0Sfi( A g g 90 D 80 R P/ashsB 70 60 n 50 Hours healed a) 325", [ASTM 06-33 mefhod) Fig. 3.

/nvenior: Alvin R Anderson By his A fforneg: O

May 21, 1949. 'A, P. ANDERSON 2,201,466

' TRANSLUCENT PETROLEUMYPLASTIG Fild-Jah. 21. 1,938 7 3 Sheets-Slieet :5

Molecular Welghf (D 0 mo 200 30o A.S.T.M. Penefrafion of 77F Fig.1

: selected petroleum oils of certain types or charusually darker than 5. 2 0

.55 as yellowoche'r, terracotta, chromic oxide, ferric tlon of the extracts are compared below with BIv Patented M., 21, 1940 h i 2,201,466

UNITED STATES PATENT OFFl CE TRANSLUCENT PETROLEUM PLASTIC 1 Alvin P. Anderson, Berkeley, Calif., asslgnor to Shell Development Company, San Francisco, Calif;, a corporation 01' Delaware 1 Application January 21, 1938, Serial No. 186,133

8 Claims. (01. 196-149) This invention deals with new and useful transoxide, titanium white, leaiwhilihlifimlwmfl la lucent plastic petroleum products and more parmarine blue, aluminum powder: etc. onrorm: ticularly is concerned with relatively light colored nately, however, the stability of these plastics is asphaltic plastics having superior properties to relatively poor and upon exposure to atmospheric '5' those of similar products heretofore known. j conditions for several months, they turn black It is known that petroleum oils consist .of ex-- andlose their translucency.

tremely complicated mixtures of difierent com- The translucency of the plastic may be meas ponents which are chiefly of the paraffin, naphured by determining the A. S. T. M. color of a .l% thene and aromatic series. Owing to the comtest solution of the plastic in asuitable substan: i m plexity of these mixtures, however, little is known tially colorless solvent such as carbon tetrachlo- 10 about the chemical structure of many of their ride, benzene, etc. In general, if the color of the members, particularly the heavier ones. Theretest solution is below about 3 A. S. T. M. the fore it is customary to characterize and describe colorof the plastic mixed with pigment is more diiierent fractions of petroleum oils by their or less bright. If the color of the test solution physical properties such as gravity, boiling range, is substantially above-3V A. S. T. M., the color 15 viscosity, penetration, temperature susceptibility, of the plastic containing the pigment is dull and color, solubility in-difierent solvents, etc. may even be black. Ordinary asphalts produce Fractionating petroleum oilsby difierent meth- .1% solutions in benzene or carbon tetrachloride ods or combination of methods, or by subjecting having A. S. T. M. colors darker than 4% ,an

acteristics and from certain sources to suchfrac- It is the purpose of this invention to provide tionating methods, has made it possible to isolate improved translucent petroleum plastics havingj petroleum fractions which are peculiarly suited properties superior to similar products known for specific purposes; and often by introducing heretofore and in particular possessing, improved relatively minor changes into the methods of temperature susceptibilities and resistance to 88 fractionation, it has been possible greatly to oxidation. improve the quality of the desired fractions for I have discovered that so-called naphthene a given purpose, or even'to produce fractions of base and; particularly, intermediate base petro-' entirely new properties. leum oils, such as are found in many of the Mid- :m It is known that by removing asphalts and low .Continent fields, contain varying amounts 01 boiling components from a typically naphthenic light-colored plastics, other than the above, which petroleum oil such as .a California crude oil, exare excellently suited for the uses described above. tracting the remaining middle fraction with a 'l'hese plastics which are designated here plastics so-called naphthenic solvent, i. e., a solvent such A, are similar in many respects to the known :23 as liquid S02, phenol, cresylic acidsQflp dichlor light-colored asphaltic plastics which are soluble vill! ethyl ether, nitrobcnzene, furfural, etc., having a in acetone and are referred to as plastic B. For

selective solvent power for non-paraflinic and parinstance, both plastics are substantially completeticularly aromatic hydrocarbons, and then disly' soluble in 86 A. P. I. naphtha, their contents tilling the extract to remove vaporizable com- .01 asphaltenes, i. .e., components insoluble in 86 40 ponents, asphalt-like plastic materials have been A. P. .I. naphtha, being normally of the order of 40 obtained which; have a relatively light color, are .5% and usually less than .1 However, plastics translucent and completely soluble in acetone. A differ from plastics Bin that they are substan- These plastics are practically identical with certially insoluble, i. e., less than about 25% soluble tain light-colored natural asphalts heretofore in equal volumes of acetone at 77 E, which known. v 1 indicates their diflerent chemical composition, 45

Translucent plastics or albino asphalts, as they confirmed by the fact that plastics A are more are sometimes called, have wide utility. 'They stable against oxidation'and have less tendency may be. used for pavings and moreparticularly to crack when used in paints. They also differ for markings on paved roadways and the like, for from the known-petroleum or asphaltic resins as an roofs, paintsfsubstitutes for resins, manufacture will be shown hereinafter. I

of linoleum, etc. While they are of various shades 'For illustrative purposes typical light-colored of green or brown to the reflected light, they are asphaltic .A plastics produced from California translucent in thin layers and may be colored" and Mid-Continent lubricating stocks by solvent brightly by admixture of suitable pigments, such extraction with'naphtheni'c solvents and distillasimilar known acetone-soluble light-colored B petroleum plastics, both natural and produced from California crude.

From the point of view of quality of asphalts. penetration index is very important. It is a measure for temperature susceptibility of as- Table I phalts. A high penetration index signifies a low Type of the plastic A B Source of petroleum oil California Mid-Continent California Natural Solubility in a by volume acetone at 77 .percent- 8 i 6 13 100 100 Specific gravity 1. 040 1. 023 1. 020 l. 060 1. 042 Penetration at 77 F. A. S. T. M 40 20 128 5 19 Softening point (ringland ball) F. A. 8. T. M 124 131. 1 106.0 126.8 127. 6 Penetration index l. i -1. 9 1. 7 -2. 0 -2. 3 Color A. S. T. M. of .l% solution of plastic in carbon tetrachloride 156 2%- 2- 295+ 8- The plastic 13 from California crude shown in 1 Table I was obtained by following the procedure described in the Merrill U. S. .Patent 2,081,498. A heavy lubricating distillate from Coalinga crude was extracted with liquid S0: to produce a raffinate fraction and an extract fraction. The extract fraction was distilled under substantially non-cracking conditions until the residue left in the still was substantially solid at normal atmospheric temperature and had plastic properties.

In order to produce the plastic A from the same crude it was necessary to re-extractthe raiflnate fraction produced above with a naphthenic solvent of greater solvent power than that of the first. Liquid S02 containing its own volume highly aromatic kerosene extract was used. A small amount of a secondary extract fraction was obtained, which upon distillation to produce a plastic residue yielded the California plastic A shown in the table. It will thus be noted that merely by differently combining the known extraction and distillation procedures, a product was obtained having. new properties, which as will be shownjare greatly superior to those of the known California and natural plastics of the type B.

A comparison of the plastics A and B in the table reveals essential difierences in two important properties: gravity and penetration index. The relatively high gravities of plastics B indicate that they are of more aromatic character than plastics A, which are apparently to a large extent of naphthenic composition. Because of their aromaticity, plastics B are practically immiscible with polyisobutylene and similar chain polymers having molecular weights in excess of about 800 obtainable by polymerization of olefines. Admixture of such oil-soluble high molecular weight polymers to asphalts not only improves their temperature susceptibilities but also increases their adhesiveness. Blends of plastics Bwith such polymers are unstable and separate upon prolonged standing. On the other hand, plastics A are capable of dissolving many of the high molecular weight polymers such as rubber, hydrogenated rubber, polymerized is'obutylene, polymerized styrene, polymerized indene, etc.,

and upon prolonged standing, blends of plastics A with such polymers do not separate.

To illustrate the above, upon addition of 5% polyisobutylene having a moleculer weight of about 3000 to plastic A having an A. S. T. M. penetration at 77 F. of 31 and a softening point of 123 F., a blend was obtained having a softening point of 134 F. and a penetration of 31. The penetration index has been improved from --2.0 to .5. v

temperature susceptibility, i. e., a low variation in consistency over a given temperature range. Obviously a high penetration index within the limits of satisfactory ductility is desirable in road asphalts and similar products.

Penetration indexes may be determined graphically from the A. S. T. M. penetration at 77 F. and the A, S. T. M. ring and ball softening point with the aid of the graph shown as Fig. 1 in the attached drawings. By connecting the softening point on the left hand scale with the penetration at 77 F. on the right hand scale with a straight edge and marking the intersection with the oblique line carrying the' penetration index scale, the desired result may be read from the latter. The penetration index can be readily obtained also by using a slide rule described in the application Serial No. 162,634, filed September 7, 1937, of Van Doormaal.

Penetration indexes of my plastics are, in general, not below about -2.1, whereas acetone soluble petroleum-products have generally penetration indexes considerably below that figure.

Other important differences between petroleum plastics A and B were found in their boiling temperatures, relative resistance to oxidation, molecular weights, solubilities in liquid S02, etc. Plastics B are readily distillable and soluble in liquid S02, and are therefore in general prepared from naphthenic extracts of distillates, whereas plastics A are diflicult to distill, and therefore are generally prepared from residual oils to avoid excessive losses as well as cracking,

In Fig. 2 of the drawings the changes of color are shown upon heating three 40-50 penetration light-colored asphaltic plastics, namely plastic A from a Mid-Continent crude which was 8% soluble in acetone, 9. plastic B from a naphthenic' base crude, and a natural plastic B, under conditions of A. S. T. M. method D 6-33 for determination of loss on heating at 325 F. The colors were determined at several intervals during the heating period by making .l% solutions of the plastics in benzene. As will be noted the color of the Mid-Continent plastic A darkens at a very much lower, rate than either of the acetone-soluble natural or California products of the type B.

In Fig. 3 is shown the change of penetration of two samples of plastics A and B having penetration at 77 F., when heated under the conditions of the A. S. T. M. test D 6-33 at 325 F. for, 50 hours. vaporization losses for both products were below .6%. The B plastic hard 'ened very'much more rapidly than the A plastic. Moreover, it was found that the asphaltene contents before and after heatingwere as follows:

Table 11 l Table In Asphaltene content P] 88m ml containing 5 Solubility of lastic in 100 volume p rcent acetone at 77 F Before h in ea 0 Specific gravity 1.010 1.022 325mg" Penetration at 77 F. 143 10 a going: poi gt (ring and ball) 10;.3 2;

one on ex &3: $1 52535 33,;

j} Color A. s. 'r. M. 4% solutionincarbon tetrachloride) 1 2% Molecular weight 485 545 Sol bility at 77 F. in equal volume of acetone. I 4. 5 6. 6 I have found that as a general rule my plastics develop less than 1% and-usually less than 5% asphaltenes upon heating for 50 hours at 325 F. under the conditions ofthe A; .S. T. M;

the same conditions.

Plastics A have considerably higher molecular weights as determined by the cryoscopic method using benzene than plastics B of the same pene'- tration, as is shown in Fig. 4, where penetration is plotted against molecular weights for two typical plastics A and B. This difference in molecular weights largely accounts for the differences between the distillabilities of the two types of plastics.

penetrations at 77 F. .up to about 300, the approximate relation of penetration and molecular .80 weights is as follows:

\ For plastics A the sum of penetration at 77 1. plus 2 times molecular weight is greater than For plastics B the sum of penetration at 77 F. plus 2 times molecular weight is smaller than When using the light-colored petroleum plastics in paints it was further observed that, in a general, paints containing B plastics deteriorate '40 at a higher rate than similar paints containing A plastics. For instance, two samples of blue paint were made by mixing in a ball mill The'only difierence between the two samples was in the type of the plastic,

Pieces of thoroughly cleaned and sandblasted sun and air. It was found that after 5 days'of exposure the paint containing B plastic had cracked and developed brown spots, whereas the product containing plastic A had remained unchanged.

In order to determine how far acetone insoluble asphaltic resins were responsible for the superior properties'of the A petroleum plastics, an A plastic, less than- 10% soluble in acetone,- derived from a-Mid-Continent lubricating residue was mixed with an excess of silica gel and the resulting mixture was extracted in a Soxhlet apparatus with 88 A. P. I. naphtha. According to Kalichevskyg and Fulton National Petroleum News 23, p ges 33 t0 36, December 23, 1931, asphaltic resins-are retainedby solid adsorbents, such as fullers earth and the like, A resin-free extract fraction so'obtained after removal of the naphtha had the following properties in comparison with the original plastic containing the resin:

The curves in Fig. 4 indicate that for metalwere coated with the paints and exposed to Plastics A as produced from deasphalted paraflinic residues usually contain between about 1-0-to asphaltic resins as determined by the clay adsorption method of Kalichevsky and Fult0li cited above, the exact amount being very difiicult to determine because of inherent inaccuracies in the method.

The light-colored A plastics-freed from resins are translucent, hard, glossy, solids of asphalta like texture. As will benoted they have better colors and penetration indexes than the same plastics containing resins and consequently have lower temperature susceptibilities and better colors than the resins themselves. resins are in general dark-colored substances, and solutions of .1% in carbon tetrachloride or benzene have A. S. T. M. colors normally considerably darker, than 3% and often darker than 6 or 7. The fact that resins are adsorbed by clay and the like while the true plastics A are not, indicates that the two classes of substances have entirely different chemical structures. This contention is further borne out by differences betwe'en their .distillabilities and ductilities as shown below. Moreover, the asphaltic resins in the natural plastic mixtures or the type A ob-' tained from residual oils by the methods described later, have considerably higher molecular weights than the true plastics A themselves.

On the other hand, the molecular weight-penetrationrelationship hereinbefore disclosed does A having an original penetrationat 77 F. or 21 and a solubility in equal volumes of acetone at '77" F. of 8%, not more than about 35% could be distilled without substantial cracking 'even though a vacuum of the order of .1 t0 .3

. mercury was maintained. The overhead product had a penetration of 151 at 77 F. and was 17% soluble in an equal .volume 01' acetone. Materially larger percentages of plastic A can be' distilled when employing molecular distillation Asphaltic -methods, under ,vacua of 10- mm. mercury or largely undistill'ed and are thus effectively separated from the true plastics A without incurring cracking.

Plastics or the type-A containing substantial quantities of asphaltenes are diflicult, ifnot impossible, to distill 1o molecularstilis, exceptin small amounts, because=of rapid gum and coke deposition on the heating'surfaces at the;

temperatures necessary. for" the distillation. Therefore i n order. to produce [substantial amounts of distilled plastics A it is necessary to charge to the molecular still a material which contains the desired plastics and is substantially free' from asphaltenes, i. e., a solution of the charging stock in benzene or carhon'tetrachloride containing .1% of the plastic A should have a cnollor not substantially darker than 3 /2 A. ,S. The distilled plastics A are clear, glossy, transparent materials substantially identical with those obtained when removing resins by adsorption on clay. They have green fluorescence and resemble in appearance solidified paraifinic bright stocks. They may have colors witho'ut dilution as light as 8 A. S. T. M. and lighter, and normally are'lighter than about 4 A. S. T. M. in 1.0% solutions of carbon tetrachloride or benzene. Solubilities in acetone of the distilled and undistilled grades are substantially the same.

In Table IV the results of distilling a typical plastic A by molecular distillation are shown. A vacuum of 10- to it)" mm. mercury was maintained while distilling.

Crude Oil" (September 1935) seven bases of petroleum oils may be distinguished, namely A- paraifin base Bparafi'in intermediate base C-intermediate paraflin base D-intermediate base E-intermediate naphthene base F-naphthene intermediate base G-naphthene base As a general rule, upon extraction with certain naphthenic solvents, heavy lubricating stocks such as cylinder oils, substantially free from asphaltenes and belonging to the classes A to D, yield extract fractions, normally solid distillation residues of which are substantially insoluble in acetone; whereas heavy stocks of classes E to G usually contain suflicient amounts of acetone-soluble plastic compounds so that naphthenic extract fractions yield upon distillation plastics which are largely or completely soluble in equal volumes of acetone. 1

Heavy extract fractions which upon distillation Table IV 1 yield residualplastics of the type A are normally Distillation temperature, "F 495 5 3 593 PlasticA Original Distillate Residue Distillate Residue Distillate Residue Yield 2,5 55.6 no.3 39.7 63.6 35.4 Penetrationet77F 21 83 3 01 1 1 1 Boiteningpoint F. 12s 109 150 113 183 114.5 164.5 gei ietrat igm elx i i w -2.1 -2.0 2.5 -7

c or so ut on 11 car on r m lilyl'fdfii-Ynui 2% v 1 8 8 0 or so ill. on n car on tetrachloi idegufl; 2 1 a 114+ 354+ 1% 4 DuctiiityatTl F 1 0 0 0 As will be noted above, the distillation residues comprising predominantly resins are relatively hard, possessing penetration indexes of -2.5 and lower and ductilities of 0, whereas the true plastics A substantially fr'ee from resins are softer and have penetration indexes not below 2.1 and ductillties of 100+.

Coming now to the manufacture of the plastics A, their chief sourcesare intermediate base petroleum oils. However, paraflin base as well as naphthene base petroleum oils may contain varying amountsthereof, as hereinbefore indicated, and their recovery depends upon the proper combination of steps which may vary f0 different types of petroleum oils.

Typically naphthene base crude oils yield mostly acetone-soluble plastics B which may beisolated according to the procedure described in the Merrill U. S. Patent 2,081,496. Small amounts of plastics A, however, may be recovered by further extracting the raffinate produced in the first extraction with a suitable naphthenic solvent and distilling the small amounts of a secondary extract so obtained, until a plastic residue is formed as hereinbefore described in connection with plastics made from California crude, shown in Table I. y

In contrast to naphthenic StOCkS QSPI laIt-IIGB heavy Mid-Continent primary extracts may yield upon distillation plastics of the A type. Whether or not secondary extraction of the primary raflinate as described for naphthenic .dis-

tillates is necessary in the manufacture of my A plastics depends largely upon the composition of the petroleum oil from which the starting material is obtained. According to Bureau of Standards Report of Investigation 3279 on Base of a substantially insoluble in equal volumes of liquid S02 at about 32 -F., and therefore in order to prepare such extract fractions, naphthenic solvents having solvent-powers greater than liquid S02 are ordinarily employed. Furfural, ppdichlor ethyl ether, phenol, cresilic acids, nitrobenzene, etc., or mixtures thereof are usually satisfactory, in that the heavy extract fractions which contain the plastic A'are soluble in about equal volumes thereof under the extraction conditions normally employed when treating heavy oils with these solvents.

Removal of asphalt from petroleum oils, containing same and substantial. amounts of plastic A, is preferably carried out by treatment with propane and /or butane, if desired in admixture with methane or ethane, under conditions to produce a deasphalted oil which is completely soluble in 86" A. P. I. naphtha. Ordinary vacuum'distillation may be usedunder some circumstances for separating the asphalts. However, this may result in injury to and considerable losses of the desired plastics A, particularly the harder grades, since the latter are practically non-distillable under non-cracking conditions by ordinary distilling means, even under extreme vacuum and in the presence of steam as has been pointed out hereinbefore. Therefore I preferto prepare my plastics fromundistilled petroleum oils of classes A to D, i. e., petroleum oils such as residual cylinder stocks which may have been toppedbut never have been taken overhead.

Deasphalted lubricating stocks of the classesB to D and occasionally of class Aare extracted i better suited is it for the production of my lightrespectively, as follows:

colored plastics. Thus I have prepared extract fractions by extraction of Oklahoma City, Seminole, Ranger, Marshall, Burbank, Tonkawa, etc., deasphalted undistilled lubricating oil stock, which extract fractions. were substantially insoluble in an equal volume of liquid S: at 32 F.

and upon distillation yielded plastic residues having solubilities in equal volumes of acetone at 77 F. and in 250% by volume liquid 80:

Table V Solubility in- Penetration at 77 F of plastic Equal volume 2507 by v0.

' of acetone at ume liquid S01 77 F. at 45 F.

Below 50 Below Below Between 50 and 150 Below 15 Below If desired, plastics A produced in the above manner maybe separated by extraction with liquid 80: to produce a residual plastic A ramnate, insoluble, in liquid $02, which has improved properties and is substantially free from substances having the properties of plastic B.

For example, a typical plastic A was subjected to extraction with 250% by volume liquid S0: at F. with the following results:

Table VI mm. Extract Plastic original fraction fraction Penetration at 71 F 114 14s is Soitenin p int (ring and bell) 105 102 129 Penetra on index -1. 9w --1.7 2.4 Color A. B. T. M.(.l% solution in carbon tetrachloride) 2+ 2- 234+ Yield, percent by weight 100 76 24 As will be noted the raflinate from the above extraction has an improved penetration index. It was found to be practically insoluble in an equal volume of acetone at '77? F.

Distillation of the extract to produce a residu substantially solid at normal atmospheric temperatures and having the desired penetration should be carried out under non-cracking conditionspi'eferably under high vacuum and/or in the presence of steam. Cracking of the plastics begins at about 625 F. Or I may fractionate.

the deasphalted stock prior to. extraction to produce a'heavy residual oil, such asa cylinder oil,

and then extract this residue with a naphthenic solvent having a solvent power greater than liquid to produce directly without further distilla-- tion a plastic of the desired penetration.

Other methods of successful separation of .the

I desired light-colored petroleum plastics may comprise treating dewaxed petroleum oils, or heavy distillates thereof, or even naphthenic extracts of intermediate base petroleum oils containing, if desired, black asphalts and/or substantial amount of aromatic fractions, with hydrocarbon or other suitable gases such as methane, ethane, propane,

carbon dioxide, etc., at high pressures. For instance, an extract having a specific gravity of 1.015 obtained by countercurrent extraction of a Mid-Continent deasphalted undistilled lubricate ing stock with propane and cresylic acids, was treated with 350 volume per cent of butane under a C02 pressure of 550 lbs. at 140 F. 20% of a dark precipitate was separated and the resulting rafiinate was distilled to produce a plastic residue having the following properties:

Table VII solubility in equal volume of acetone at 77 F per cent- 8 Penetration A. S. T. M. at 77 Fu 48 Softening point (ring and ball) F.. 117.1 Penetration index --2.1

Color A. S. T. M. (.1% solution in carbon tetrachloride) -i 2 In another series of experiments adewaxed Mid-Continent deasphalted stock having 9. Saybolt Universal viscosity at 210 F. of 105 seconds and a pour point of 10 F. was fractionated by treating same with 530% by volume of a methane-propane mixture at 68 F. and under'a pressure of 800 lbs. The residue amounting to 25% of the chargewas dissolved in 540 volume per cent liquid butane at 20 C. A precipitate equal to .8% of the oil was discarded. The rafllnate amounting to 34.2% of the oil was further fractionated by step-wise introducing natural gas at increasing pressures of 700 lbs., 800 lbs., and 900 lbs., respectively, and separating the precipitated fraction after each addition of gas. The three precipitates so obtained had the following properties:

Table VIII Precipitate 1st 2nd 3rd Yield roent of oil any a 2.3 -Perletrg i t ion at 77 1 28 E a 1% Softening point (ring and ball) "I? 130.1 12.1 105.5 Penetration index- -1.8 -1.6 1.4 Color A. 8. '1. M; (.1 percent solution in can.

bon tetrachloride 3g 3 3 Solubility in equal volume of acetone at 77 F- 5 a a as my inventions 1. A natural petroleum plastic, translucent in thin layers, substantially free from asphaltenes,

Substantially solid at atmospheric temperature,

substantially completely soluble in 86 A. P. I. naphtha, more than 75% insoluble in an equal "volume of acetone at 77 F., and having a temperature susceptibility lower than that of as-' phaltic resins.

2. Anatural petroleum plastic, translucent in substantially solid at room temperature, substantially completely soluble in 86 A. P. I. naphtha,

-more than 75% insoluble in an equal volume of acetone at 77 F'., and having a penetration index not lowerthan '2.1.

3. A natural petroleum plastic, translucent in thin layers, substantially free from asphaltenes, substantially solid at room temperature, substantially completely'soluble in 86 A. P. I. naphtha,

more than 75% insoluble in an equal volume of acetone at 77 F'., substantially resistant to oxidation and having a ductility at '7 F. of

' thin layers, substantially free from asphalten'es,

4. A natural petroleum plastic, translucent in thin layers, substantially free from asphaltenes, substantially solid at atmospheric temperature, substantially completely soluble in 86 A. P. I naphtha, having an A. S. T. M. penetration below 50, a solubility at 77 F. in an equal volume of acetone below 10%, and a temperature susceptibility lower than that of asphaltlc resins.

5. A natural petroleum plastic substantially solidat atmospheric temperature, substantially free from asphaltenes and asphaltic resins, completely soluble in 86 A. P. I. naphtha, more than 75% insoluble in an equal volume of acetone at 77 F. and having an A. S. I. M. color of 8 or lighter,

6. A natural petroleum plastic, translucent in thin layers, substantially free from asphaltenes.

substantially solid at room temperature, substan-- tially completely soluble in 86 A. P. I. naphtha. more than 75% insoluble in an equal volume of acetone at 77 F., and containing less than 40% asphaltic resins.

a 7. A natural petroleum plastic, translucent in thin layers, substantially free from asphaltenes, substantially solid at room temperature, substantially completely soluble in 86' A. P. I. naptha, containing less than 40% asphaltic resins, havi an A. S. T. M. penetration at 77 F, below 300 and a relation of penetration to molecular weight: A. S. T. M. penetration at 77 F. plus 2 times molecular weight is greater than 1050.

' .8. A natural petroleum plastic comprising a perature, substantially completely soluble in 86 A. P. I. naphtha, more than 75% insoluble in an equal volume or acetone and having a ductility at 77 F. of 100+.

' ALVIN P. ANDERSON. 

